public class demo9 {

    public static long count = 0;
    public static void main(String[] args) throws InterruptedException {
        Object o = new Object();
        Thread t1 = new Thread(()->{
            for (int i = 0; i < 50000; i++) {
                    synchronized (o){
                        synchronized (o){
                            count++;
                        }

                    }
            }
        });
        Thread t2 = new Thread(()->{
            for (int i = 0; i < 50000; i++) {
                       synchronized (o){
                           count++;
                       }
            }
        });
        t1.start();
        t2.start();

        t1.join();
        t2.join();
        System.out.println(count);
    }
}
